Device and method for facilitating hemostasis of a biopsy tract

ABSTRACT

A system including an adaptor and a syringe is used for facilitating hemostasis of a biopsy tract or other puncture wound by delivery of an absorbable sponge in a hydrated state into the wound. The adaptor includes a tapered lumen for hydrating and compressing the relatively large absorbable sponge for delivery through a relatively small cannula, such as a biopsy needle. The hydrated absorbable sponge is injected through the biopsy needle into the biopsy tract by fluid. Alternatively, the sponge may be delivered to the biopsy needle by injection of fluid and then delivered to the biopsy tract by a plunger or stylet. The implanted absorbable sponge facilitates hemostasis at the biopsy site or other puncture wound and minimizes the chance of internal bleeding. The absorbable sponge material is absorbed by the body over time.

[0001] This application is a continuation-in-part of U.S. applicationSer. No. 09/071,670 filed May 1, 1998, which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to a wound closure device, and moreparticularly, the invention relates to a device and method forfacilitating hemostasis of a biopsy tract or other puncture wound byinjection of an absorbable sponge.

[0004] 2. Brief Description of the Related Art

[0005] Percutaneous needle biopsy of solid organs is one of the mostcommon interventional medical procedures. Millions of percutaneousneedle biopsies are performed annually in the United States andthroughout the world. Percutaneous biopsy is a safe procedure which hassupplanted surgical biopsy for many indications, such as skin biopsy andliver biopsy.

[0006] Possible complications of needle biopsy include bleeding at thebiopsy site. The amount of bleeding is related to a number of factorsincluding needle size, tissue sample size, patient's coagulation status,and the location of the biopsy site. Vascular organs such as the liver,a common biopsy target, may bleed significantly after needle biopsy. Tominimize bleeding from a biopsy site, small-gauge needles are typicallyused. Small gauge needles, however, produce less satisfactory biopsyspecimens but frequently are favored over larger bored needles becauseof their perceived safety. In order to minimize the chance of internalbleeding after biopsy, external pressure is applied and patients areoften asked to lie in uncomfortable positions, such as the lateraldecubitus position, for a number of hours, particularly after liverbiopsy.

[0007] Sterile sponges, such as Gelfoam, are prepared in dry sterilesheets which are used as packing material during surgery for control ofbleeding. The sponge sheets are left in the surgical site after surgeryto stop bleeding and are absorbed by the body in 1 to 6 weeks. A numberof techniques have used these absorbable sterile sponge materials toplug a biopsy tract to minimize or prevent bleeding. The absorbablesponge provides a mechanical blockage of the tract, encourages clotting,and minimizes bleeding though the biopsy tract. Despite the advantagesof using absorbable sponge to plug a biopsy tract this technique has notachieved widespread use because of difficulty in preparing anddelivering the sponge material into the biopsy tract.

[0008] One example of a biopsy wound closure device using an implantablesponge is described in U.S. Pat. No. 5,388,588. According to thispatent, a circular sponge of an absorbable foam material is precut andinserted into a biopsy site by an applicator rod having the spongepositioned on the end. Once the sponge is implanted, the sponge absorbsblood and swells to fill the tract preventing further bleeding at thebiopsy site. However, the sponge is difficult to deliver and expandsslowly once delivered. In addition, this delivery method can onlydeliver a sponge of a limited size which provides less local compressionthan desired and may incompletely fill the target site. Further,bleeding may continue along sections of the biopsy tract where no spongehas been delivered.

[0009] Accordingly, it would be desirable to provide a device and methodwhich will permit the delivery of an absorbable sponge to a biopsy tractin a simple and reliable manner.

SUMMARY OF THE INVENTION

[0010] The present invention relates to a device and method forfacilitating hemostasis of a biopsy tract or other puncture wound byinjecting an absorbable sponge. The system according to the presentinvention allows the sponge to be delivered in a hydrated state throughthe biopsy needle or other cannula directly into the puncture wound.

[0011] In accordance with one aspect of the present invention, a systemfor injecting a sponge into tissue includes a pledget of sponge having aproximal end with a larger cross sectional area than a distal end, acannula for delivering the pledget in a hydrated state to the tissue,and an adaptor connectable to the cannula for hydrating and deliveringthe pledget to the cannula, the adapter having a tapered lumen with alarge diameter proximal end and a small diameter distal end, wherein thesmall diameter distal end is connectable to the cannula.

[0012] In accordance with an additional aspect of the present invention,a method of forming a sponge pledget for delivery to tissue includessteps of cutting a strip of sponge from a sheet of sponge material andfolding the strip to form a pledget with a first end having a firstcross sectional area and a second folded end having a second crosssectional area which is larger than the first cross sectional area.

[0013] In accordance with a further aspect of the present invention, asystem for preparing and delivering a hydrated sponge to a cannula fordelivery to tissue includes an adaptor and a template. The adaptorincludes an elongated member having a first end, a second end, and alumen extending from the first end to the second end, a luer connectorprovided at the second end for connection to a cannula, a taperedsection of the lumen tapering from a first diameter at the first end toa second diameter at the second end which is smaller than the firstdiameter such that a dry sponge pledget having a width larger than thesecond diameter is compressible when hydrated to allow passage of thepledget into the second diameter. The template is configured for use incutting the sponge to a size to be received in the elongated member fordelivery to the cannula.

[0014] In accordance with an additional aspect of the invention, anadaptor system for delivering a hydrated sponge to a cannula fordelivery to tissue includes an elongated adaptor having a distal end, aproximal end, a lumen tapering from a larger diameter at a proximal endto a smaller diameter at the distal end, and a luer connection at thedistal end, and a removable vent cap configured to engage the luerconnection, the vent cap having a vent hole which allows fluid to passout of the adaptor through the cap but prevents the sponge from passingthrough the vent hole.

[0015] In accordance with another aspect of the invention, a method ofdelivering a sponge into a tissue access tract includes the steps ofdelivering a hydrated sponge pledget through a cannula positioned in atissue access tract at a velocity E while withdrawing the cannula fromthe tissue at a velocity V to deposit the sponge pledget and seal thetissue access tract, wherein the velocity E is greater than or equal tothe velocity V.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention will now be described in greater detail withreference to the preferred embodiments illustrated in the accompanyingdrawings, in which like elements bear like reference numerals, andwherein:

[0017]FIG. 1 is a perspective view of a punch for forming pledgets;

[0018]FIG. 2 is a side cross sectional view of an adaptor for deliveryof a pledget to a needle;

[0019]FIG. 3 is a side cross sectional view of a syringe for connectionto the adaptor;

[0020]FIG. 4 is a side cross sectional view of an adaptor and syringecombination with a pledget positioned within the adaptor;

[0021]FIG. 5 is a side cross sectional view of an adaptor and syringecombination in accordance with an alternative embodiment in which thepledget has been hydrated and moved into a small diameter end of theadaptor;

[0022]FIG. 6 is a side cross sectional view of the loaded adaptor andsyringe combination in preparation for connection to a biopsy needle;

[0023]FIG. 7 is a side cross sectional view of an alternative embodimentof an adaptor connected to a biopsy needle and syringe;

[0024]FIG. 8 is a side cross sectional view of an alternative embodimentof an adaptor;

[0025]FIG. 9 is a side cross sectional view of an alternative embodimentof an adaptor with enlargements in the lumen for kneading the pledget;

[0026]FIG. 10 is a side cross sectional view of an alternativeembodiment of an adaptor with irregularities in the lumen for kneadingthe pledget;

[0027]FIG. 11 is a side cross sectional view of an alternativeembodiment of an adaptor for delivery of a pledget including a templateattached to the adaptor;

[0028]FIG. 12 is a bottom view of the adaptor and template of FIG. 11;

[0029]FIG. 13 is a top view of the template as it is used for cutting apledget from an absorbable sponge sheet;

[0030]FIG. 14 is a side cross sectional view of a distal end of anadaptor with a vent cap attached;

[0031]FIG. 15 is a side cross sectional view of the adaptor and vent capof FIG. 14 having a pledget staged within the adaptor; and

[0032]FIG. 16 is a side cross sectional view of a portion of an organand a system for delivering a pledget into a biopsy tract in the organ.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The system of the present invention delivers an absorbable spongematerial in a hydrated state to facilitate hemostasis of a biopsy tractor other puncture wound in a simple and safe manner. The apparatus fordelivering a hydrated absorbable sponge will be described below inconnection with treatment of a biopsy tract after a percutaneous needlebiopsy. However, the invention may be used for facilitating hemostasisof other types of puncture wounds or tissue access tracts to preventbleeding of these wounds.

[0034] The system for facilitating hemostasis of the biopsy tractincludes a punch 10 for cutting a pledget 18 of absorbable spongematerial from a sheet of this material, an adaptor 12 for delivering thepledget to a biopsy needle 16, and a syringe 14 for hydrating andinjecting the pledget. The adaptor 12 allows a relatively large pledgetof absorbable sponge material to be compressed and inserted into thebiopsy tract in a hydrated state. The absorbable sponge material for usein facilitating hemostasis may be any absorbable sponge which is capableof deforming upon hydration to be delivered by fluid pressure rough abiopsy needle or other cannula.

[0035] Prior to discussing the present invention in further detail, thefollowing terms are defined:

[0036] “Pledget” means a piece of absorbable sponge of a generallyelongated shape having a size which allows injection in a hydrated statethrough a biopsy needle or other cannula.

[0037] “Sponge” means a biocompatible material which is capable of beinghydrated and is resiliently compressible in a hydrated state.Preferably, the sponge is non-immunogenic and may be absorbable ornon-absorbable.

[0038] “Absorbable sponge” means sponge which when implanted within ahuman or other mammalian body is absorbed by the body.

[0039] “Hydrate” means to partially or fully saturate with a fluid, suchas, saline, water, contrast agent, thrombin, therapeutic agent, or thelike.

[0040] “Kneading” of the absorbable sponge material means both dry andwet manipulation of sponge material which compresses, enlarges, orchanges the shape of the sponge material causing the sponge material tohave improved expansion response.

[0041]FIG. 1 illustrates one example of a punch 10, also called a dyecutter, for cutting an absorbable sponge sheet 20 into pledgets 18 of anappropriate size for delivery to a biopsy tract. The punch 10 includes arectangular blade 22 fixed to a plate 24 having a handle 26. The punch10 is pressed down onto a flat sheet 20 of commercially availableabsorbable sponge to cut the pledget 18 of an appropriate size. Inaddition to the punch 10 illustrated in FIG. 1 other cutting devices,such as, a scissor type hand punch, an automatic punching machine, or atemplet and knife may be used for preparation of the pledget 18. Analternative pledget forming system will be discussed in further detailbelow with respect to FIGS. 11-13.

[0042]FIG. 2 shows the adaptor 12 according to the present invention inwhich the pledget 18 is placed for hydration and for delivery throughthe biopsy needle 16. The adaptor 12 allows pieces of absorbable spongematerial with relatively large cross sections to be easily deliveredthrough a biopsy needle 16 with a much smaller cross section. Theadaptor 12 also functions to remove air from the pledget 18.

[0043] The adaptor 12 which delivers the hydrated pledget 18 to theneedle 16 includes a first end 30 having an annular lip 32 or femaleluer fitting for connection to the syringe 14. A second end 34 of theadaptor 12 has a male luer fitting 36 for connection to a biopsy needle16 or other cannula. The luer fitting 36 includes a tapered externalsurface 38 and a retaining ring 40 with internal threads for receivingan annular lip of the biopsy needle. The adaptor 12 has an internallumen with a first diameter D₁ at the first end 30 and a second diameterD₂ at the second end 34. Between the first and second ends of theadaptor 12 a tapered section 42 of the adaptor provides a funnel forcompressing the hydrated pledget 18 prior to injection through thebiopsy needle 16 and needle hub 28.

[0044] The adaptor 12 may be formed in any known manner such as bymolding from a plastic material. Preferably, the adaptor 12 istransparent so that the pledget 18 can be viewed through the adaptor andthe user can visually monitor when the pledget is loaded within theadaptor and when the pledget has been delivered into the needle. Theadaptor lumen may be provided with a friction reducing coating forimproved delivery. The delivery fluid also reduces friction for improveddelivery by wetting the exterior surface of the pledget 18.

[0045] The syringe 14 includes a male luer fitting 46, a fluid chamber48, and a plunger 50. The first end 30 of the adaptor 12 is connectableto the luer fitting 46 of the conventional syringe 14. The syringe i4may be provided with a spring 52 for automatic filling of the syringe 14with a predetermined volume of fluid. Alternatively, the syringe mayinclude a threaded syringe plunger, as shown in FIG. 7, for accurateinjection of small quantities of fluid. The syringe volume will varydepending on the amount of fluid needed for hydration and delivery ofthe pledget 18 through the biopsy needle 16.

[0046] A biopsy needle 16 for use with the present invention ispreferably a coaxial biopsy needle, such as a bi-axial or a tri-axialbiopsy needle. A co-axial biopsy needle includes an outer needle orcannula through which a tissue sample is removed with a tissue scoop orother biopsy instrument. Once the tissue sample has been removed, theouter cannula remains in the patient as illustrated in FIG. 6. Althoughthe cannula for delivery of the sponge pledget has been described as abiopsy needle, the cannula may be a catheter, sheath, or any other typeof cannula.

[0047] A preferred method of facilitating hemostasis of a biopsy tractwill be described with reference to FIG. 4 which shows the loading andhydration of the pledget 18 within the adaptor 12. A pledget 18 is cutas described above and placed within the adaptor 12 from the first end30 of the adaptor. The syringe 14 is filled with a predetermined amountof fluid, such as saline, and is connected to the first end 30 of theadaptor 12 by the luer fitting 46. The plunger 50 of the syringe 14 isthen depressed slowly causing fluid to pass into the adaptor 12,hydrating the pledget 18, and filling the adaptor with a column offluid. Care should be taken to inject the fluid slowly to prevent thepledget from being ejected out of the second end 34 of the adaptor.Preferably, the user waits a few seconds once the fluid is injected intothe adaptor 12 until the pledget 18 is adequately hydrated creating alubricous surface on the pledget. The pledget 18 may expand within theadaptor to fill or nearly fill the lumen of the adaptor. The adaptor 12with the pledget 18 hydrated within the proximal end is ready to injectthe pledget into a biopsy tract to facilitate hemostasis within thebiopsy tract. The adaptor 12 may be loaded prior to beginning the biopsyprocedure.

[0048] After the biopsy procedure has been completed, the outer sheathof the biopsy needle 16 through which the biopsy has been taken ismaintained in place within the biopsy tract, as shown in FIG. 6. Thebiopsy needle 16 provides pre-established targeting of the delivery sitefor delivery of the absorbable sponge pledget 18 and eliminates theuncertainty of re-access. The luer fitting 36 of the adaptor 12 isconnected to the biopsy needle hub 28, as illustrated in FIG. 6. Thebiopsy needle 16 is withdrawn a short distance, such as about 1 to 20mm, along the biopsy tract to provide space for the pledget 18 to bereceived in the biopsy tract. Additional fluid is then rapidly injectedby the syringe to move the pledget 18 into the biopsy needle 16. Whenthe adaptor lumen has been blocked by the hydrated pledget 18 which hasswelled within the adaptor, injection of additional fluid will push thepledget through the tapered section 42 of the adaptor. If the adaptorlumen has not been entirely blocked by the pledget 18, the venturieffect will help draw the pledget through the tapered section 42 of theadaptor. After the pledget 18 is moved to the biopsy needle 16, thepledget 18 is then delivered from the needle 16 to the biopsy tract byrapid injection of additional fluid by the syringe 14. The hydratedpledget 18 quickly expands upon delivery to fill the available space inthe biopsy tract to facilitate hemostasis and provide localizedcompression.

[0049] As illustrated in the cross sectional view of FIG. 7, one exampleof a needle hub 28 has an interior diameter D₃ which is larger than thediameter D₂ at the distal end 36 of the adaptor 12. The large internaldiameter needle hub 28 allows the hydrated pledget 18 which has beencompressed by the tapered section 42 of the adaptor to expand in theneedle hub before being compressed again into the needle lumen. Thiscompression and enlargement of the hydrated absorbable sponge material,does not adversely effect the pledget delivery and in fact improves theexpansion response of some delivered sponge materials as will bediscussed in further detail below.

[0050] A smooth tapered transition between the lumen of the needle hub28 and the needle lumen helps to provide for easy injection of thepledget 18. However, needles having internal steps between the needlehub 28 and the needle 16 have been used and the pledget 18 is stillinjected successfully. According to an alternative embodiment of theinvention, the needle hub 28 may be designed to have a inner diameterapproximately the same as the inner diameter D₂ at the distal end 36 ofthe adaptor.

[0051] Preferably, specific measured doses of fluid are used to achieveeach of the steps of the treatment procedure depending on the pledgetsize and the dimensions of the adaptor 12, the needle 16, and the needlehub 28. The pledget 18 should be completely delivered into the biopsytract by the fluid and only a minimal amount of extraneous fluid shouldbe delivered. For example, the pledget 18, once inside the needle, maybe delivered with about 0.02 to 1.5 ml of fluid depending on the size ofthe needle 16 used. Injection of larger amounts of fluid may distend thebiopsy tract or displace the pledget within the organ.

[0052] According to one example, a pledget 18 having a size ofapproximately 20 mm by 2 mm cut from a sheet of commercially availableGelfoam having a thickness of approximately 1.5 mm can be hydrated andinjected through a standard 18 gauge, approximately 15 cm long biopsyneedle with approximately 0.9 ml of fluid. An adaptor according to thisexample has a first diameter D₁ of about 0.38 cm, a second diameter D₂of about 0.14 cm, a total length of about 3.80 cm, and a taper angle ofabout 45°. About 0.3 ml of fluid is injected slowly to hydrate thepledget 18 and fill the adaptor with a column of fluid. Approximately0.3 ml of fluid is then injected to load the pledget 18 from the adaptor12 into the biopsy needle 16. Finally, about 0.3 ml of fluid is injectedto deliver the pledget 18 into the biopsy tract. Loading of the pledgetfrom the adaptor 12 into the needle 16 and delivery from the needle tothe biopsy tract can be combined in one step by delivery ofapproximately 0.6 ml. Accurate and complete injection of the pledgetwith a minimum amount of extraneous fluid is achieved by this volumetricinjection technique.

[0053] According to an alternative embodiment of the adaptor illustratedin FIG. 5, vent holes 44 extend through the side walls of the adapter 12adjacent the second end 34 for venting fluid during loading of thepledget 18. As illustrated in FIG. 5, the user places a finger over thesecond end 34 of the adaptor 12 to prevent the pledget from exiting theadaptor. The plunger 50 of the syringe 14 is then depressed slowlycausing fluid to pass into the adaptor 12 and hydrate the pledget.Preferably, the user waits a few seconds once the fluid is injected intothe adaptor 12 until the pledget 18 is hydrated. Once the pledget 18 ishydrated, additional fluid is then injected quickly into the adaptor 12to move the pledget 18 from the first end 30 of the adaptor towards thesecond end 34 of the adaptor. As the pledget 18 is compressed by thetapered section 42 of the adaptor 12 air and fluid are allowed to escapefrom the adaptor through the vent holes 44. Once the pledget 18 has beenmoved into the position illustrated in FIG. 5 adjacent the second end34, fluid injection is halted. The adaptor 12 with the hydrated pledget18 within the distal end is ready to insert the pledget through a biopsyneedle to facilitate hemostasis within the biopsy tract.

[0054] As an alternative to placement of a finger at the distal end ofthe adaptor 12 during advancement of the pledget 18 through the taperedsection 42, a removable cap may be used. Further, the vent holes 44 maybe omitted and a screen or a cap having a screen may be used to allowfluid to pass through the screen while the screen prevents the pledget18 from being ejected. One example of a vent cap will be described infurther detail below with respect to FIGS. 14 and 15.

[0055] An alternative embodiment of the delivery system is illustratedin FIG. 7 in which an adaptor 12 is provided with a pressure indicator64 to monitor pledget injection. Preferably, the pressure indicator 64is removably attached at a luer fitting 66 provided on a side of theadaptor 12. The pressure indicator 64 includes a pressure dome 68movable from the convex shaped extended position illustrated in FIG. 7to a flat position depending on the pressure inside the adaptor 12.Internal pressure within the biopsy needle 16, the adaptor 12, and thesyringe 14 will drop as the pledget 18 is extruded from the biopsyneedle into the biopsy tract. This causes the pressure dome 68 to movefrom the convex position illustrated in FIG. 7 to a flat position,indicating that pledget delivery is complete.

[0056]FIG. 8 illustrates an alternative embodiment of an adaptor 12 a inwhich the tapered section 42 a is shorter and more abrupt. Theparticular size and shape of the adaptor 12 a according to either FIG. 2or FIG. 8 may vary depending on the size of biopsy needle, the tissuesample size, and the size of piedget to be delivered. One example of theadaptor 12 a of FIG. 8 for delivery of an absorbable sponge pledget 18through an approximately 18 gauge biopsy needle has a first adaptordiameter D₁ of about 0.25 cm or greater, preferably about 0.30 to 0.80cm and a second adaptor diameter D₂ of about 0.25 cm or less,preferably, about 0.05 to 0.23 cm. An angle made by a wall of thetapered section 42 a with a longitudinal axis of the adaptor 12 a mayvary from about 5° to 90°, but is preferably between about 30° and 60°.The tapered section 42 a is illustrated with a substantially planarinterior surface, when shown in cross section. However, the taperedsection 42 a may also have a convex or concave surface in cross section.The dimensions described for the adaptor 12 a are appropriate for usewith an approximately 18 gauge biopsy needle commonly used for liverbiopsies. For some of the much larger biopsy needles or cannulas usedfor skin or breast biopsies the adaptor dimensions would be scaled upaccordingly.

[0057]FIG. 8 also shows a connector 70 for connecting the adaptor 12 toa syringe 14 when the proximal end of the adaptor is larger in diameterthan the standard syringe fitting. The connector 70 includes a first end72 for connection to the syringe 14 and a second end 74 for connectionto the adaptor 12.

[0058] One type of absorbable sponge material which is acceptable foruse in the present invention is Gelfoam, manufactured by the UpjohnCompany. Gelfoam is a porous, pliable, cross-linked gelatin material andis available commercially in sheet form as pre-compressed ornon-compressed sponge. The material may be provided preformed as apledget 18 or may be cut with a punch 10, or a stencil or template andknife to form a pledget as described above. Once hydrated, the pledget18 can be easily compressed to fit into a lumen having a smaller crosssectional area than the original cross sectional area of the pledget.Additionally, the kneading of the hydrated pledget 18 during deliveryencourages air trapped within the Gelfoam to be expelled and replacedwith fluid, allowing rapid expansion upon delivery. When a pledget 18 ofa pre-compressed Gelfoam is hydrated and kneaded (expelling air) duringdelivery, the pledget will have the absorbtion capacity to rapidlyexpand to many times (e.g., 3 or more times) its original dry volumeupon delivery. When a pledget 18 of the non-compressed Gelfoam ishydrated and kneaded (expelling air) during delivery, the pledget willhave the absorbtion capacity to rapidly expand to its original dryvolume upon delivery. These properties make the Gelfoam sponge materialparticularly useful for facilitating hemostasis of biopsy sites.

[0059] Abrupt lumen diameter changes within or between the adaptor 12 orthe needle 16 will improve “kneading” of the absorbable sponge materialimproving hydration of the absorbable sponge material thereby improvingthe expansion properties of the hydrated delivered absorbable sponge.According to the alternative embodiments of the adaptor illustrated inFIGS. 9 and 10, enlarged, recessed, or irregular areas in the lumen ofthe adaptor are provided to impart additional kneading action to theabsorbable sponge material further improving expansion properties of thesponge.

[0060] The adaptor 12 b of FIG. 9 includes two enlarged areas 72 of thelumen. As the absorbable sponge pledget 18 passes through the lumen ofthe adaptor 12 b the material expands and is compressed by the adaptorto increase kneading of the pledget. FIG. 10 illustrates anotheralternative embodiment of the adaptor 12 c including a lumen with aplurality of staggered irregularities 74 for improved kneading of theabsorbable sponge pledget 18. The irregularities 74 will preferably havea relatively smooth surface to prevent the absorbable sponge materialfrom becoming caught on the irregularities.

[0061]FIG. 11 illustrates an alternative embodiment of an adaptor 112with a pledget formation template 122 attached to the adaptor. As shownin FIG. 11, the adaptor 112 includes a proximal end 130 having a femaleluer 132 and a distal end 134 having a male luer 136. The pledget 118 isinserted in the proximal end 130. A tapered section 142 is providedwithin the adaptor 112 for compressing the pledget 118 into the biopsyneedle.

[0062] When delivering a pledget 118 of absorbable sponge material, itis important to deliver a desired amount of the sponge material using aminimum amount of fluid. Some devices and methods which allow thedelivery of sponge material with a minimum amount of fluid include theuse of the pledget configuration illustrated in FIG. 11, the use of avent cap for staging of the pledget as illustrated in FIGS. 14 and 15,and the withdrawal of the biopsy needle during delivery as illustratedin FIG. 16.

[0063] Pledgets 118 having increased proximal cross sectional areas aremore easily delivered than pledgets with constant cross sectional areasor decreased proximal cross sectional areas. FIG. 11 illustrates apledget 118 having a proximal cross sectional area which isapproximately twice its distal cross sectional area. The smallermaterial mass at the distal end of the pledget 188 increases the ease ofinserting the pledget into the adaptor 112. The smaller distal end ofthe pledget also passes through the delivery cannula or biopsy needlewithout creating a large back pressure to resist the delivery of thepledget through the cannula. The larger proximal section of the pledget118 provides a better seal within the interior of the adaptor 112 andthe cannula 16 which allows a minimum amount of fluid to be used toadvance the pledget. The increased material at the proximal end of thepledget 118 also increases the amount of sponge material delivered tothe biopsy tract.

[0064] Pledgets 118 with increased cross sectional area proximal endsmay be prepared in a variety of manners. For example, if a pledget 118is prepared from a sheet of sponge material, the increased proximal masscan be achieved by cutting the pledget with an enlarged proximal end.Alternatively, the pledget 118 may be formed by folding, rolling,compressing, or otherwise manipulating the sponge material to thedesired shape. The proximal pledget mass may also be increased by addingseparate pieces of material to the proximal end of the pledget. Thisadditional material may be layered, wrapped, coiled or attached to thepledget in any other manner. The pledgets may also be formed by molding,bump extruding, dipping, or the like. The larger cross sectional areaproximal end is generally about 1.2 to 4 times the cross sectional areaof the distal end. In addition, the proximal end with the larger crosssection area preferably extends along about ⅛ to ¾ of the total pledgetlength.

[0065] The pledget 118 illustrated in FIG. 11 has been formed by cuttinga strip of material from an absorbable sponge sheet 20 with the aid ofthe template 122 as illustrated in FIG. 13. After the strip is cut, theproximal end of the strip is then folded back onto itself to form apledget 118 with an increased cross sectional area and material mass ata proximal end. One example of a preferred embodiment of a Gelfoampledget for delivery down a 20 gauge biopsy needle or cannula has a sizeof approximately 0.1×1.5×0.06 inches and is folded as illustrated inFIG. 11 to an overall length of about 0.9 inches. Placing this pledget118 in an adaptor 112 having a largest internal diameter of 0.125 inchesallows the pledget to be delivered to a 20 gauge or larger biopsyneedle. Other common biopsy procedures use an 18 gauge or larger biopsyneedle through a slightly larger guide cannula and would receive asomewhat larger pledget. After taking a core sample and removing thebiopsy needle from the cannula guide, a pledget 118 maybe deliveredthrough the cannula to the biopsy site. The pledget 118 for use in thesystem employing an 18 gauge or larger biopsy needle may be formed froma strip which is approximately 0.11-0.12 inches wide by about 3.125inches long with a thickness of about 0.06 inches and folded to anoverall length of about 2.2 inches. This pledget having a singlethickness distal end and double thickness proximal end can be deliveredfrom an adaptor having a largest internal diameter of approximately0.125 inches.

[0066] One method for forming the pledget 118 with the enlarged proximalend with the aid of a template 122 is illustrated in FIG. 13. Thetemplate 122 is a flat plate having recesses 124 along one or more edgesof the template. The recesses 124 have a width and a length whichcorresponds to a preferred width and length of the pledget. The recesses124 form a raised bar 126 at a location where the pledget should befolded. When the template is pressed onto a sheet 20 of absorbablesponge material, the bar 126 makes an indentation or groove in thesponge material. A user cuts along the side 128 and end 129 edges of thetemplate 122 with a blade to form a strip of the sponge material whichis then folded along the groove or crease formed by the bar 126 to formthe pledget 118. It is important to securely hold the sponge sheet byapplying downward pressure to the template 122 during cutting to preventtearing and breaking of the sponge material. Prior to folding the stripof sponge material to form the pledget, the strip may be compressed witha flat surface of the template to compact the sponge and assist inloading the pledget into the adaptor 112.

[0067] Although the template 122 has been illustrated as a plate whichis attached to the adaptor 112, it should be understood that thetemplate can also be a separate member. In addition, the template 122may provide guides for forming pledgets of different sizes for deliverythrough different sized biopsy needles. The template 122 may be providedwith or without the creasing bar 126 and may be transparent or opaque.In the opaque version, the edges of the recesses 124 are used to alignthe template with an edge of the sponge sheet 20. In contrast, in atransparent version of the template, the recesses 124 may be eliminatedand a visual indication or line may be provided which assists inaligning an edge of the sponge sheet with the template.

[0068]FIGS. 14 and 15 illustrate a preferred vent cap 70 for use withthe adapter 112. As discussed above with respect to FIG. 5, vents maybeused to assist in hydrating and staging the pledget within the adapter.In particular, vents will allow the pledget to be moved to a preferredaxial location within the adapter 112 prior to delivery. In addition,the vents allow fluid to be injected and air to be removed from thepledget prior to delivery. The vent cap 70 as illustrated in FIG. 14includes a female luer connector 72 including a flange 74 which isreceived on the male luer 136 of the adapter 112. The vent cap 70 alsoincludes a conical portion 76 which is configured to extend into adistal end 134 of the adaptor 112. The conical portion 76 has one ormore fluid paths or vent holes 78 which allow air and fluid to exitthrough the vent cap but prevent the absorbable sponge material of thepledget 118 from passing through the vent cap. The vent hole mayalternatively be positioned between the vent cap 70 and the adapter 112.Preferably, an exterior of the conical portion 76 forms a seal with thelumen of the adaptor 112 at the distal end. The diameter of the venthole 78 is approximately 0.005-0.02 inches, preferably approximately0.01 inches. This small vent hole 78 allows the purging and venting offluid and air from the adapter 112 but does not allow the pledget 118 topass through the venthole, even at high pressures such as 5 psi orgreater. The use of the vent cap 70 allows the user to apply highpressures with the syringe used to hydrate the pledget. The highpressures drive the fluid into the pledget causing rapid and thoroughhydration of the sponge material. Repeated pulsing of the fluid with thesyringe will provide more complete hydration of the pledget.

[0069] The vent cap 70 also positions the pledget 118 at a preferredaxial position just proximal to the distal end 134 of the adapter 112 asillustrated in FIG. 15. This positioning of the pledget 118 away fromthe end of the adaptor prevents the pledget from becoming trappedbetween the adaptor 112 and the biopsy needle hub 28 which is attachedto the distal end of the adaptor. In addition, after hydration of thepledget and removal of the vent cap 70 the sponge material may tend toswell out of the distal end of the adapter 112. Accordingly, the conicalportion 76 of the vent cap 70 preferably extends into the adaptor 112approximately 0.01 to 0.1 inches, more preferably about 0.01 to 0.03inches.

[0070] According to the present invention, the portion of the vent cap70 which extends into the lumen of the adaptor 112 can be any desiredshape such as dome-shaped, cylindrical, conical or other shape.

[0071] As described above, the pledget maybe delivered to the biopsytract by holding the biopsy needle or cannula 16 stationary andinjecting the pledget through the biopsy needle. If additional pledgetsare to be delivered, the biopsy needle 16 is withdrawn a distancesufficient to accommodate an additional pledget and the additionalpledget is then injected.

[0072] According to an alternative embodiment of the invention, themethod of delivering the pledget into the biopsy tract may includewithdrawing the biopsy needle or cannula 16 during delivery of thepledget 18 to deliver the pledget in an elongated trail which followsthe biopsy tract. Placing the absorbable sponge material in a trailwhich fills the entire biopsy tract provides the added benefit ofproviding hemostasis along the entire biopsy tract. This is particularlyhelpful for stopping the bleeding of biopsy tracts in organs which tendto have excessive bleeding such as the liver, kidney, spleen, and othervascular organs.

[0073] In order to achieve a trail of absorbable sponge material in thebiopsy tract, one method of the present invention involves the deliveryof the pledget into the biopsy needle by a predetermined amount offluid. The biopsy needle is then withdrawn at a velocity V while thepledget material is ejected from the biopsy needle at a velocity E withrespect to the biopsy needle. The velocity V at which the biopsy needleis withdrawn is equal to or less than the velocity E at which theabsorbable sponge material is delivered. The control of injection offluid and withdrawal of the needle to achieve the desired trail ofabsorbable sponge material in the biopsy tract maybe controlled with aninjection controlling device.

[0074] According to an alternative embodiment of the inventionillustrated in FIG. 16, the adaptor maybe used to deliver the pledgetinto the biopsy needle 16 and then the adaptor is removed from thebiopsy needle. A plunger or stylet 80 which is generally provided withthe biopsy needle 16 for inserting the biopsy needle is then used todeliver the pledget from the biopsy needle. As shown in FIG. 16, thebiopsy needle extends through the tissue 84 and into the organ 86 forremoval of a core of tissue. After biopsy, the pledget is injected intothe needle 16 and the plunger 80 is placed within the biopsy needle sothat a distal end of the plunger abuts the proximal end of the pledget118. The plunger 80 is then held stationary while the biopsy needle 16is withdrawn from the biopsy site. The plunger 80 causes the pledget 118to be delivered in a trail 88 which fills the biopsy tract. The trail 88preferably extends along the entire biopsy tract to or past a surface ofthe organ 86. The delivery of the trail 88 of absorbable sponge materialprovides an advantage over the delivery of discrete blobs of materialbecause the trail is able to provide hemostasis along the entire tract.In contrast, if a blob of absorbable sponge material is delivered withinthe tract at a depth of 1-2 cm from the surface of the organs, this 1-2cm of biopsy tract may continue to bleed significantly.

[0075] As an alternative to delivery of the pledget as a trail, thepledget may be delivered as a plug. To deliver a plug the plunger 80 isadvanced into the needle 16 pushing the pledget out of the distal end ofthe needle while the needle is held stationary. A combination ofdelivery of plugs and trails may also be used. The pledget material maybe delivered entirely within a single anatomical structure or may crosstwo or more anatomical structures such as an organ, surrounding tissueand facial layer.

[0076] Although the invention is primarily intended for delivery ofabsorbable sponge, non-absorbable sponge may also be delivered with thedevices, systems, and methods of the present invention. A non-absorbablesponge may be desirable where it will be necessary to locate the biopsysite or tract after the procedure.

[0077] Although the pledget 18 has been shown and described as having arectangular cross section, pledgets of other shapes may also be used.For example, the pledget may be preformed in any shape, such as with arectangular or circular cross section or may be rolled from a thin sheetof absorbable sponge material. The pledget 18 may have a multi-sidedcross section, a star shaped cross section, or a folded cross sectionand may have through or blind holes formed in the dry pledget. Inaddition, the pledget size and shape can be matched to the size andshape of a particular delivery site. Pledget shapes having greatersurface area provided by features such as fins provide faster hydration.

[0078] The continuous structure of the absorbable sponge pledget 18provides more secure and reliable placement than a paste or liquid andcan even facilitate partial withdrawal, removal, or movement of thedelivered pledget.

[0079] In some instances it may be desirable to deliver multiplepledgets in spaced apart positions along the biopsy tract, particularlyfor a long biopsy tract. For delivery of additional pledgets, the biopsyneedle 16 is retracted a distance sufficient to provide a space toaccommodate an additional pledget 18 and the injection proceduredescribed above is repeated for the additional pledget(s). For aparticularly large biopsy site or cavity, additional pledgets 18 may beinjected beside an initially injected pledget until the cavity isfilled.

[0080] Although biopsy is most commonly performed by biopsy needle,biopsy may also be performed through other cannulas, such as catheters,long needles, endoscopes, or the like. The treatment procedure accordingto the present invention can be used for facilitating hemostasis ofpuncture wounds through different types of cannulas including needles,catheters, endoscopes, and the like. In addition, the treatmentprocedure and systems according to the present invention may be used todeliver absorbable or non-absorbable sponge for other therapys. Forexample, sponge may be delivered for cosmetic or reconstructive bulkingor for temporary or permanent intravascular embolization.

[0081] The absorbable sponge pledget 18 may be used to deliver abeneficial agent, such as contrast agent, thrombin, radiation treatment,or the like. The pledget can also be used to deliver therapeutic agents,such as radioactive isotopes for localized treatment of tumors,anti-cancer agents, anti-metastatic agents, and the like. Examples ofanticancer agents include 5-fluorouracil, cisplatin, prednisone, andothers described in U.S. Pat. No. 4,619,913 which is incorporated hereinby reference. The absorbable sponge pledget 18 may be presoaked with thebeneficial agent for delivery to the biopsy tract. Alternatively, thepledget 18 may be hydrated with the beneficial liquid agent or the agentmay be delivered to the pledget after the pledget is placed within thebiopsy tract.

[0082] A pledget formed of commercially available Gelfoam material willbe absorbed by the body within 1 to 6 weeks. However, the pledgetmaterial may be designed to provide different rates of absorption. Forexample, Gelfoam can be designed to be absorbed at different rates byvarying the degree of cross-linking. Preferably, the pledget is designedto be absorbed in less than one month.

[0083] The treatment of a biopsy tract with a hydrated and injectedpledget 18 of absorbable sponge to facilitate hemostasis providessubstantial advantages in comfort over external pressure methods. Inaddition, the present invention also provides advantages over theinsertion of an absorbable sponge material in a dry state with anapplicator. In particular, the adaptor 12 allows a relatively largepledget to be compressed and inserted into the biopsy tract in ahydrated state. The injected pledget 18 conforms in shape quickly to theshape of the biopsy tract and immediately begins blocking blood flow. Incontrast, a dry piece of sponge material must be cut to the particularsize of the biopsy tract and does not swell to fill the tract until theblood has sufficiently saturated the sponge material which can takesignificantly longer and provides inadequate local compression.

[0084] While the invention has been described in detail with referenceto the preferred embodiments thereof, it will be apparent to one skilledin the art that various changes and modifications can be made andequivalents employed, without departing from the present invention.

What is claimed is:
 1. A system for injecting a sponge into tissue, thesystem comprising: a pledget of sponge having a proximal end with alarger cross sectional area than a distal end; a cannla for deliveringthe pledget in a hydrated state to the tissue; and an adaptorconnectable to the cannula for hydrating and delivering the pledget tothe cannula, the adapter having a tapered lumen with a large diameterproximal end and a small diameter distal end, wherein the small diameterdistal end is connectable to the cannula.
 2. The system of claim 1,wherein the pledget is formed from a sheet of sponge material which isfolded to form the larger cross sectional proximal end.
 3. The system ofclaim 1, wherein the pledget proximal end has a cross sectional area ofabout 1.2 to 4 times a cross sectional area of the distal end.
 4. Thesystem of claim 1, wherein the pledget proximal end with the largercross sectional area extends along ⅛ to ¾ of total length of thepledget.
 5. The system of claim 1, wherein the sponge is an absorbablesponge material.
 6. A method of forming a sponge pledget for delivery totissue, the method comprising: cutting a strip of sponge from a sheet ofsponge material; and folding the strip to form a pledget with a firstend having a first cross sectional area and a second folded end having asecond cross sectional area which is larger than the first crosssectional area.
 7. The method of claim 6, wherein the strip is cut withthe aid of a template.
 8. The method of claim 7, wherein the template isattached to a device for hydrating and delivering the pledget.
 9. Themethod of claim 6, wherein a crease is formed in the strip by a cuttingtemplate and the strip is folded along the crease.
 10. A system forpreparing and delivering a hydrated sponge to a cannula for delivery totissue, the system comprising: an adaptor comprising: an elongatedmember having a first end, a second end, and a lumen extending from thefirst end to the second end; a luer connector provided at the second endfor connection to a cannula; and a tapered section of the lumen taperingfrom a first diameter at the first end to a second diameter at thesecond end which is smaller than the first diameter such that a drysponge pledget having a width larger than the second diameter iscompressible when hydrated to allow passage of the pledget into thesecond diameter; and a template configured for use in cutting the spongeto a size to be received in the elongated member for delivery to thecannula.
 11. The adaptor of claim 10, wherein the template includes arecess sized and shaped to form an elongated strip of sponge.
 12. Theadaptor of claim 10, wherein the template includes a cutting edge forcutting along with a blade to form a strip of sponge and a creasing barfor forming a crease across the strip.
 13. The adaptor of claim 10,wherein the template is attached to the elongated member.
 14. An adaptorsystem for delivering a hydrated sponge to a cannula for delivery totissue, the system comprising: an elongated adaptor having a distal end,a proximal end, a lumen tapering from a larger diameter at a proximalend to a smaller diameter at the distal end, and a luer connection atthe distal end; and a removable vent cap configured to engage the luerconnection, the vent cap having a vent hole which allows fluid to passout of the adaptor but prevents the sponge from passing through the venthole.
 15. The adaptor system of claim 14, wherein the vent cap isconfigured to position a distal end of the sponge at a predeterminedlongitudinal position with respect to the adaptor.
 16. The adaptorsystem of claim 15, wherein the predetermined longitudinal position isproximal of the distal end of the adaptor.
 17. The adaptor system ofclaim 14, wherein the vent cap includes a conical portion configured toextend into the distal end of the adaptor.
 18. Tne adaptor system ofclaim 17, wherein the vent hole is provided at a tip of the conicalportion.
 19. A method of delivering a sponge into a tissue access tractcomprising: delivering a hydrated sponge pledget through a cannulapositioned in a tissue access tract at a velocity E while withdrawingthe cannula from the tissue at a velocity V to deposit the spongepledget and seal the tissue access tract, wherein the velocity E isgreater than or equal to the velocity V.
 20. The method of claim 19,wherein the velocity E is provided by injection of a fluid.
 21. Themethod of claim 19, wherein the velocity E is provided by a plunger. 22.The method of claim 19, wherein a portion of the tissue access tractbeing filled spans two or more anatomical structures.